Sample doesnt stick to C18 column

[tifaniin]

Hi,
I am trying to synthesize and purify Shikimate-3-phosphate (S3P) using a C18 column. The reaction that I use for the synthesis of S3P contains shikimate, ATP, KCl, MgCl2 and Tris pH 7.0. It might due to the presence of the buffer components, but the sample does not stick to the column and comes straight off. I am using 0.1% TFA as mobile phase. Could anyone please advice me as to how I could make my sample stick to the C18 column? Thank you

[tom jupille]

Possibly addition of an ion-pairing reagent (e.g., tetrabutylammonium) would work, but my guess is that separation would be much easier using HILIC .

[Vlad Orlovsky]

need something like this:
http://www.sielc.com/Compound-Alendronic-Acid.html
http://www.sielc.com/Compound-Isopropyl ... -Acid.html

[danko]

Using ion pair in purification context is not my prefered solution.
I would much rather go for Ion Exchenge mode.

Best Regards

[Arne]

It's likely too polar for C18 RP separation. Ion exchange will be the way to go imo.